Recycling of air humidifier cylinders

ABSTRACT

There is provided a method for recycling steam producing cylinders such as used for humidification purposes. The method comprises opening the old cylinder ( 10 ), removing the electrodes ( 12 ) from respective electrode support rods ( 16 ), cleaning the cylinder ( 10 ) to remove all deposits therefrom, forming new electrodes ( 48 ) of a non magnetic material to have a thermal exchange similar to the removed electrodes ( 12 ), soldering the new electrodes ( 48 ) to respective electrode support rods ( 16 ), and rescaling the cylinder ( 10 ).

This application is a 371 of PCT/CA99/00273 filed Mar. 30, 1999 whichclaims benefit of provisional app. Ser. No. 60/080,208 filed Mar. 31,1998.

The present invention relates to humidifiers and more particularly,relates to a method for recycling steam producing cylinders such as areused for humidification purposes.

BACKGROUND OF THE INVENTION

Steam producing humidifiers are utilized in many buildings formaintaining the humidity within the building at a desired level. Thesteam producing cylinders usually comprise an outer casing or containerof a plastic material within which there is placed water and at leasttwo electrodes for passing an electric current through the water to heatthe same and thereby produce steam. The outer container or cylinder ismade of a material which is resistant to the steam and/or hot water andis usually of a polypropylene material. The electrodes are immersed inthe water and alternating current is supplied to the electrode. Thecurrent travels through the water and produces the heat which then boilsthe water.

For any given voltage, the amount of current determines the amount ofsteam produced. Generally, for new cylinders, it is established thatapproximately 1 pound of steam requires ⅓ of a kilowatt of electricalenergy.

A major problem associated with the steam producing cylinders is scalingof the electrodes and other parts. In an attempt to minimize thisproblem, purging of the containers at regular intervals is recommendedand required.

As will be understood, the continuous boiling of the water leaves anincreased mineral accumulation in the remaining water. This mineralaccumulation increases the conductivity of the water and thus the amountof current flowing. However, this also results in the scaling of theelectrodes and in turn, the scaling on the electrodes acts as ainsulating layer thus decreasing the efficiency of the steam producingcylinder.

It is well understood that given a certain voltage, the value of thecurrent will change depending on various parameters including the sizeof the cylinder and/or the amount of the water for a given electrodesize. One can also change the conductivity of the water as abovementioned wherein the current will increase in proportion to the waterconductivity. One can also vary the space between the electrodes and/orvary the size and thickness of the electrodes.

The source of the water itself will be a factor in the operation of thesteam producing cylinder. Thus, the amount of dissolved minerals willvary from one city to another as well as from one well to another. Asaforementioned, purging the cylinders is required at frequent levels.

The calcification on electrodes is one problem. Deposits also form onthe inner walls of the container and some of the deposits from theelectrodes and/or the inner water walls may separate and accumulate on amesh or screen filter at the bottom of the cylinder. Naturally, blockingthe mesh filter will accelerate the rate of deposits due to lack ofpurging and eventually plug the entire cylinder rendering it inoperable.Furthermore, one may find cylinders which are partially melted due toarcing and some cylinders have been known to catch fire or even explode.

Apart from the straight scaling problem, corrosion is a further problemwhich eats away at the electrodes. These electrodes are of a ferrousmaterial and are susceptible to arcing between electrodes. This arcingcan weaken and destroy the electrodes.

The electrodes themselves are normally of a perforated material whichincreases the circulation and contact with water that travels throughthe apertures or pores in the electrode. However, the apertures andpores rapidly become clogged due to scaling and indeed, the small sizethereof renders them very susceptible to the same.

For the reasons mentioned above, the steam generating often becomeinoperable and must be completely discarded. Often, due to the scalingproblems, the electrodes damage separators which are used within thecylinders and the cylinders must be discarded.

It has been proposed in the art to help overcome the problem of scalingby coating the electrodes with various materials. While such methodshave achieved varying degrees of success, they have not been widelyadopted.

Conventional constructions of electrodes seen in the prior art areshown, for example, in U.S. Pat. No. 4,288,684. However, this patentdoes not teach any recycling of steam generating cylinders.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodfor recycling steam generating cylinders used for the production ofsteam.

It is a further object of the present invention to provide an improvedsteam generating cylinder which is less susceptible to scaling andclogging.

According to one aspect of the present invention, there is provided amethod of recycling steam producing cylinders having a plurality ofelectrodes mounted on respective electrode support rods, and whichcylinders have deposits formed therein, the method comprising the stepsof a) opening the cylinder, b) removing the electrodes from respectiveelectrode support rods; c) cleaning the cylinder to remove all depositstherefrom; d) forming new electrodes of a non magnetic material to havea thermal exchange similar to the electrodes removed in step (b); e)soldering the new electrodes to respective electrode support rods; andf) resealing the cylinder.

As aforementioned, the known electrodes used in the steam generatingcylinders are formed of a magnetic material—i.e. a ferrous material. Thereason for the use of a magnetic material is that an electrode formed ofsuch materials is an excellent conductor of electrical energy.Generally, such materials will have an average electrical resistance at20° C. of less than 60 microhm-cm.

According to the present invention, the electrodes are made of a nonferrous and non magnetic material. Once such desirable material is 300series stainless steel. Although this material normally has a higherelectrical resistance (72-74 microhm-cm) compared to known materials, ithas been found that cylinders using such electrodes have substantialadvantages. The material has been found to be as efficient as the knownmagnetic or ferrous material conventionally used since within only a fewweeks of operation, the conventional electrodes accumulate sufficientscaling to have a resistance higher than that of the non magneticelectrode.

It has been found that the life span of cylinders using the non magneticelectrodes is an average of three times longer than the ferrouselectrodes. In addition, the non ferrous electrodes provide a largeenergy savings.

A further advantage of the electrodes of the present invention is areduction in bio-contaminants. Scale is a very porous material whichactively promotes the incubation of bio-contaminants including variousbacteria, yeast, molds, viruses, protozoa, antigens, algae andendotoxins. The electrodes of the present invention do not suffer fromthis disadvantage and a simple cleaning of the cylinders with a weakacid minimizes the problem with bio-contaminants.

In a preferred embodiment of the present invention, the conventionalcircular electrodes are replaced by a diamond shaped electrode. Once onecalculates the electrical resistant values, the electrodes may be formedin the desired configuration.

The method of the present invention provides for recycling of the steamproducing generators. This reduces the amount of waste as the cylindersare normally completely discarded. In accordance with the method of thepresent invention, the cylinders are recycled.

Generally, most cylinders are of a sealed configuration although thereare a few commercially available cylinders which may be open andsubsequently closed and sealed. In the practice of the method of theinvention, the cylinder is opened (if so constructed) or otherwise cutopen along the cylinder circumference. The electrodes (and the electroderods in certain cases) are removed.

Subsequently, the interior of the cylinder may be cleaned mechanicallyand can be followed by placing the cylinder in a solution of phosphoricacid which is environmentally friendly. New electrodes are then formedand bent to a diamond shape. The electrodes are then placed on theexisting electrode rods (or new rods are installed if required). Theelectrodes are soldered to the electrode rods and the cylinder issubsequently froze and secured together, normally using a polypropyleneplastic soldering gun and polypropylene cord.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the invention, reference will be made tothe accompanying drawings illustrating embodiments of the invention, inwhich:

FIG. 1 is a side elevational view, partially in section, of a typicalsteam producing cylinder used for humidification purposes;

FIG. 2 is a view similar to FIG. 1 illustrating the first stages ofscaling;

FIG. 3 is a view similar to FIG. 1 illustrating the scaling at a moreadvanced stage;

FIG. 4 is a side elevational view, partially in cutaway, of one type ofsteam producing cylinder which has been recycled;

FIG. 4A is a top plan view of an original electrode;

FIG. 4B is a top plan view of a replacement electrode;

FIG. 5 is a side elevational view similar to FIG. 4 illustrating aslightly different type of steam producing cylinder which has beenrecycled; and

FIG. 6 is a detailed side elevational view of an electrical supply andsupport rod.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in greater detail, there is illustrated inFIG. 1 a conventional steam producing cylinder such as may be used forhumidification purposes. Cylinder 10 has a side wall 11 which is of agenerally cylindrical configuration. In the illustrated embodiment, apair of electrodes 12 are mounted interiorly of cylinder 10 with aseparator 14 therebetween. As previously mentioned, any number of suchelectrodes may be supplied.

Each electrode 12 is mounted on an electrode supply and support rod 16which passes through an upper wall 15 of cylinder 10 and is sealed asindicated by reference numeral 18.

Appropriate electrical supply lines 20 are operatively connected toelectrical supply and support rods 16.

Cylinder 10 has a bottom part occupied by water 22 above which there isa steam chamber 24. A steam outlet 26 is provided in upper wall 15 ofcylinder 10.

At the bottom of cylinder 10, there is provided a drainage opening 30for purging the cylinder 10 when required.

FIG. 2 illustrates a first stage of deterioration in which scale 34starts to form on one of electrodes 12.

In FIG. 3, a more advanced stage of scaling is shown wherein there isadditional scale 36 which forms on wall 11 as well as scale 38 onseparator 14. As a result of the scale formation, debris 40 may blockscreen filter 28.

FIGS. 4 to 6 illustrate the modifications made to the cylinders forpurposes of recycling the same. It will be understood that as manydifferent cylinders have slightly different configurations and methodsof manufacturing, some minor modifications to the process may berequired.

In FIGS. 4 to 6, reference numerals similar to those used in FIGS. 1 to3 are used for similar components.

In the embodiment of FIG. 4, the side wall 11 is cut circumferentiallyafter marking a reference alignment mark 44 so as to provide an upperand lower body portion. Subsequently, electrodes 12 are removed fromelectrical supply and support rods 16. Scale 36 on cylinder 10 and scale38 on separator 14 as well as deposits or debris 40 on screen 26 areremoved, preferably by water jet. If need be, separator 14 and/orelectrode supply and support rods 16 may be removed and replaced. Thecylinder is also preferably soaked in a phosphoric acid to assist inremoval of all scaling on electrodes.

As shown in FIG. 4A, electrodes 12 are normally of a circularconfiguration and attached to electrode supply and support rod 16.According to the present invention, a new electrode 48 of a diamondconfiguration is spot welded to electrical supply and support rod 16.Electrode 48 is of a non magnetic material as previously described.

The upper and lower portions of cylinder 10 may then be reassembled withalignment being done by means of an alignment mark 44.

As will be noted in the embodiment of FIG. 4, there is provided a highwater level electrode, as is known in the art, and which is generallydesignated by reference numeral 46.

In the embodiment of FIG. 5, a similar process is followed with thedifference that in this particular type of cylinder, there is provided abottom electrode support 50.

As shown in FIG. 6, at the point where electrode support rod 16 passesthrough upper wall 15, there may be provided washers 54 with sealingelements 56 mounted on the rod in a conventional manner.

For reassembling the two portions of the cylinder together, at the pointwhere the walls meet, each may be beveled inwardly so as to form anangle of approximately 60° as indicated by reference numeral 58.Subsequently, a plastic welding material may be placed in the V-groovethus formed and the cylinder portions welded together.

As an addition to the above, an insulating jacket may be formed aboutthe exterior of the cylinder to thereby conserve energy when thecylinders are used.

I claim:
 1. A method of recycling a steam producing cylinder (10) havinga plurality of electrodes (12) mounted on respective electrode supportrods (16), and which cylinders have deposits (36, 38) formed therein,the method comprising the steps of: a) opening said cylinder (10); b)removing said electrodes (12) from respective electrode support rods(16); c) cleaning said cylinder (10) to remove all deposits therefrom;d) forming new electrodes (48) formed of a non magnetic material to havea thermal exchange similar to said electrodes (12) removed in step (b);e) soldering said new electrodes (48) to respective electrode supportrods (16); and f) resealing said cylinder (10).
 2. The method of claim 1wherein said step of opening said cylinder comprises the step of cuttinga cylinder wall to form two container parts and subsequently, in step(f), sealing said two container parts together.
 3. The method of claim 1wherein step (b) additionally includes the step of removing saidelectrode support rods (16) and replacing said electrode support rodswith new electrode support rods prior to step (e).
 4. The method ofclaim 1 wherein said step of cleaning said cylinder to remove alldeposits therefrom comprises the step of using water jets to removematerial and soaking said cylinders in a phosphoric acid solution. 5.The method of claim 1 wherein said step of forming new electrodes of anon magnetic material comprises forming said electrodes in a diamondconfiguration.
 6. The method of claim 5 wherein said electrodes areformed of 300 series stainless steel.
 7. The method of claim 2 whereinsaid step (f) comprises forming a V-shaped recess where said containerwall was cut and inserting plastic welding material therein.